1871-37-0Relevant academic research and scientific papers
Nickel-Catalyzed Cross-Coupling of Aryl Redoxactive Esters with Aryl Zinc Reagents
Shih, Bo-Hao,Basha, R. Sidick,Lee, Chin Fa
, p. 8862 - 8866 (2019/09/30)
A nickel-catalyzed aryl-aroyloxyl C(sp2)-O radical cross-coupling reaction conducted using a redox active ester with aryl zinc reagent was developed. This method demonstrates a new disconnection approach for formation of aryl aryl esters. In the one-pot sequential process, the readily available aryl carboxylic acids can be converted into functionalized aryl aryl esters and heteroaryl esters. This protocol is amenable to the gram-scale synthesis. The present method has a wide substrate scope and high functional group tolerance.
Metal-Free O-Arylation of Carboxylic Acid by Active Diaryliodonium(III) Intermediates Generated in situ from Iodosoarenes
Dohi, Toshifumi,Koseki, Daichi,Sumida, Kohei,Okada, Kana,Mizuno, Serina,Kato, Asami,Morimoto, Koji,Kita, Yasuyuki
, p. 3503 - 3508 (2017/09/13)
The metal-free arylative coupling of carboxylic acids using iodosoarenes without the use of a catalyst and base, which is applicable to even a highly-polar molecule bearing multiple alcohol groups, is reported. The in situ preparation of the reactive diaryliodonium(III) carboxylates is the important key to this approach, and the introduction of the trimethoxybenzene auxiliary enables both the smooth salt formations and the selective aryl transfer events during the couplings. (Figure presented.).
Fluorine-containing diaryliodonium salt and application thereof
-
Paragraph 0059; 0060; 0061; 0062, (2017/01/02)
The invention relates to fluorine-containing diaryliodonium salt as well as a preparation method and an application thereof. The fluorine-containing diaryliodonium salt has a structure represented as a formula I and is taken as an arylation reagent. The fluorine-containing diaryliodonium salt has the advantages that the preparation is easy, when the fluorine-containing diaryliodonium salt is applied to an arylation reaction, the arylation reaction condition is relatively mild, the selectivity of an arylation product is good and the like; in the formula I shown in the specification, R1 represents an aromatic ring group or a heteroaromatic ring group or represents a substituted aromatic ring group or a substituted heteroaromatic ring group, and Y represents a univalent organic or inorganic acid radical anion.
Metal-free arylation of oxygen nucleophiles with diaryliodonium salts
Jalalian, Nazli,Petersen, Tue B.,Olofsson, Berit
supporting information, p. 14140 - 14149,10 (2012/12/12)
Phenols and carboxylic acids are efficiently arylated with diaryliodonium salts. The reaction conditions are mild, metal free, and avoid the use of halogenated solvents, additives, and excess reagents. The products are obtained in good-to-excellent yields after short reaction times. Steric hindrance is very well tolerated, both in the nucleophile and diaryliodonium salt. The scope includes ortho- and halo-substituted products, which are difficult to obtain by metal-catalyzed protocols. Many functional groups are tolerated, including carbonyl groups, heteroatoms, and alkenes. Unsymmetric salts can be chemoselectively utilized to obtain products with hitherto unreported levels of steric congestion. The arylation has been extended to sulfonic acids, which can be converted to sulfonate esters by two different approaches. With recent advances in efficient synthetic procedures for diaryliodonium salts the reagents are now inexpensive and readily available. The iodoarene byproduct formed from the iodonium reagent can be recovered quantitatively and used to regenerate the diaryliodonium salt, which improves the atom economy. Copyright
Visible-light-triggered direct benzoyloxylation of electron-rich arenes at room temperature without chelation assistance
Rao, Honghua,Wang, Ping,Li, Chao-Jun
supporting information, p. 6503 - 6507 (2013/01/15)
A RuII photocatalytic method was developed for the direct mono-benzoyloxylation of electron-rich aromatic and heteroaromatic systems even with an excess amount of benzoyl peroxide. The reaction was conducted at room temperature under visible light. The direct ArC-H benzoyloxylations occur without the assistance of any directing groups and can also tolerate various functional groups that have already shown diverse reactivities in transition-metal catalysis.
Metal-free synthesis of aryl esters from carboxylic acids and diaryliodonium salts
Petersen, Tue B.,Khan, Rehan,Olofsson, Berit
, p. 3462 - 3465 (2011/08/07)
An efficient arylation of carboxylic acids with diaryliodonium salts has been developed, giving aryl esters in high yields within short reaction times for both aromatic and aliphatic substrates. The transition-metal-free conditions are compatible with a range of functional groups, and good chemoselectivity is observed with unsymmetric diaryliodonium salts. Furthermore, steric hindrance in the ortho positions is well tolerated both in the carboxylic acid and in the diaryliodonium salt, yielding aryl esters that cannot be obtained via other esterification protocols.
Magnesium bistrifluoromethanesulfonimide as a new and efficient acylation catalyst
Chakraborti, Asit K.,Shivani
, p. 5785 - 5788 (2007/10/03)
Magnesium bistrifluoromethanesulfonimide catalyzed the acetylation of phenols, alcohols, and thiols under solvent-free conditions at room temperature and in short times. Electron-deficient and sterically hindered phenols provided excellent yields. The catalyst was found to be general for acylation with other anhydrides, such as propionic, isobutyric, pivalic, chloroacetic, and benzoic anhydrides. The rate of acylation was influenced by the electronic and steric factors associated with the anhydride. The reaction with less electrophilic anhydrides (e.g., chloroacetic and benzoic anhydrides) required higher temperature (~80 °C). Chemoselective acetylation, pivalation, and benzoylation took place with acid-sensitive alcohols without any competitive dehydration/rearrangement.
Electrostatic catalysis by ionic aggregates: Scope and limitations of Mg(ClO4)2 as acylation catalyst
Chakraborti, Asit K.,Sharma, Lalima,Gulhane, Rajesh,Shivani
, p. 7661 - 7668 (2007/10/03)
Alkali and alkaline earth metal perchlorates exhibit electrostatic catalysis in the activation of anhydrides for the acylation reaction. Perchlorates with higher values of the charge-size function of the metal ion exhibit better catalytic activity following the order Mg(ClO4) 2>Ba(ClO4)2>LiClO4. Acylation of structurally diverse phenols, thiols, alcohols, and amines have been carried out with stoichiometric amounts of anhydride at room temperature under solvent free conditions in the presence of catalytic amount of Mg(ClO4) 2. Sterically hindered and electron deficient phenols are efficiently acylated. Acylation with sterically hindered anhydrides such as iso-butyric, pivalic, and benzoic anhydrides are carried out with phenols and alcohols in excellent yields. Acid-sensitive alcohols are acylated in excellent yields without any competitive side reactions.
Scandium trifluoromethanesulfonate as an extremely active Lewis acid catalyst in acylation of alcohols with acid anhydrides and mixed anhydrides
Ishihara, Kazuaki,Kubota, Manabu,Kurihara, Hideki,Yamamoto, Hisashi
, p. 4560 - 4567 (2007/10/03)
Scandium trifluoromethanesulfonate (triflate), which is commercially available, is a practical and useful Lewis acid catalyst for acylation of alcohols with acid anhydrides or the esterification of alcohols by carboxylic acids in the presence of p-nitrobenzoic anhydrides. The remarkably high catalytic activity of scandium triflate can be used for assisting the acylation by acid anhydrides of not only primary alcohols but also sterically-hindered secondary or tertiary alcohols. The method presented is especially effective for selective macrolactonization of ω-hydroxy carboxylic acids.
The Role of Aroyloxyl Radicals in the Formation of Solvent-derived Products in Photodecomposition of Diaroyl Peroxides. The Reactivity of Substituted Cyclohexadienyl Radicals and Intermediacy of ipso Intermediates
Takahara, Shigeru,Urano, Tishiyuki,Kitamura, Akihide,Sakuragi, Hirochika,Kikuchi, Osamu,et al
, p. 688 - 697 (2007/10/02)
Photolyses of bis(2-thiophenecarbonyl)peroxide (TPO) in benzene and toluene afforded, among free-radical products, biphenyl and dimethylbiphenyls, respectively, which were solely derived from the aromatic solvents.The yields of biphenyls depended upon the rate with which the radical intermediates were generated from the peroxides in sufficiently high concentrations for their dimerization.Photolyses of TPO and dibenzoyl peroxide in 1,3,5-trimethylbenzene afforded also a solvent-derived products, 2,3',4,5',6-pentamethyldiphenylmethane.Its formation provides clear evidence for participation of cyclohexadienyl radicals bearing the aroyloxyl group on the methyl-substituted ipso carbon atom.
